1. Field of the Invention
The present invention relates to an improvement of a transfer jack transferring mechanism of the so-called three or four beds type flat knitting machine comprising (i) needle beds which contain knitting needles received in movable relation in needle grooves and are arranged in front and rear confronting each other and (ii) transfer beds which are located over the needle beds and contain transfer jacks received in movable relation in jack grooves, to receive loops from knitting needles of the needle beds and then transfer the received loops to the other knitting needles arranged in the lateral side.
2. Description of the Prior Art
Many proposals have been made hitherto on this kind of flat knitting machine by, for example, Japanese Patent Publications No. Sho 41(1966)-7907 and No. 56(1981)-21854 and Japanese Laid-open Patent Publications No. Hei 1(1989)-168943 and No. Sho 63(1988)-256752. However, the prior art had no mechanism to enable a carriage or transferring cain to be moved adversely at any position on the needle bed when a loop is transferred between the knitting needle and the transfer jack, for the reason of which the carriage was forced to move in reciprocation along the entire width of the needle bed. As a result of this, the prior art had a problem that the number of the knitting courses per unit time was reduced and thus productivity was reduced significantly. Especially, this problem comes to be more pronounced as the knit width forms a decreasing proportion of the entire length of the needle bed.
To solve this problem, the applicant previously proposed a flat knitting machine disclosed by U.S. Pat. No. 5,398,527 (which corresponds to Japanese Laid-open Patent Publication No. Hei 6(1994)-136641). This flat knitting machine is provided with a transfer jack selecting means and is structured so that the carriage and the transferring cam can be moved adversely at any position on the needle bed, to increase the number of the knitting courses per unit time and thus increase productivity remarkably, while also, the transferring mechanism including the transfer jack selecting means can be arranged in a dead space of the flat knitting machine without an excessive increase of the size of the transferring mechanism.
This flat knitting machine is, however, structured such that the transfer jacks are received in swingable relation in jack grooves arranged in rows in the transfer jack beds so that their selected butts extending from upper surfaces of the transfer jacks can project or retract from upper surfaces of the jack grooves. Before a selecting portion provided in the carriage pass the transfer jacks, all selected butts of the transfer jack are pushed back to the positions projecting from the jack grooves by return cams, for the present. Then, the groups of the transfer jack selected butts not required for the knitting are pushed down into the jack grooves by means of convex cam portions operated to swing by means of actuators at the selecting portion, so that only the groups of transfer jack selected butts still projecting from the upper surface of the jack grooves without being acted upon by the convex cam portions can be engaged with the operating cam to shift the transfer jacks to the transferring positions.
Thus, the flat knitting machine previously proposed by the applicant requires the mechanism for forcing the transfer jacks to be swung in the jack grooves. In addition, every time the carriage passes the transfer jacks, all the transfer jacks are forced to be engaged with the cam portions, whether they are required for the knitting or not. As a result of this, there is a fear of the engaging portions of the transfer jacks being worn by abrasion and the like.